This invention relates to a turboshaft gas turbine engine.
For many applications of turboshaft engines, it is desirable that available engine torque increase as output shaft speed decreases. This effect is obtainable to some extent with present free-power-turbine engines which provide about 200% of design-point torque when the output shaft is stationary. However, it is desirable that torque be multiplied still further to more nearly match the power unit to its load with minimal intervening means such as gearing or torque converter.
British Pat. No. 587,528 to Power Jets Limited and A. R. Howell, proposes a turbine power plant which includes the use of rotatable stator elements. The stated chief object is to provide for taking off power at low rotational speeds. However, the torque multiplication that the disclosed embodiments provide at less than design speed conditions is less than that of conventional free-power-turbine engines.